Compare the electric and gravitational forces that exist between an electron and a proton.
OR
Explain Gauss law. A uniformly charged sphere has a total charge of 300 uc and a radius of 8 cm. Find the electric field at

a point 16 cm from the centre of the sphere.

a point on the surface of the sphere.

a point 4 cm from the centre of the sphere i.e. at a point inside the sphere.

Three capacitors are connected in series across a 75 volts supply. The voltage across them are 20, 25 and 30 volts respectively. The charge on each capacitor is 3 x C. Find the capacitance of each capacitor and also of the combination.

A current of 1 A passes through a copper wire of radius of cross-section 1 mm. Find the current density and the drift velocity of electron. The atomic weight of copper is 63·55, density 8·96 gm/cc. Avogadro's number is 6·022 x 10^26 atoms.
OR
State and explain Kirchhoff's rule for electrical circuits.

A particle of mass 0·5 kg is executing Simple Harmonic Motion. The period of oscillation is 0·1 s and the amplitude is 0·1 m. Calculate

the force

spring constant

potential energy
OR
Explain the theory of diffraction grating and derive expressions for maxima and minima.

The critical angle.(8c) for the total internal reflection in case of water is 48°. What is its polarization angle? What is the angle of refraction corresponding to this polarization angle?

A thin film has a refractive index 1·45. Determine its minimum thickness. if it appears black on reflection. 6 x
OR
Explain ordinary ray and extraordinary ray

Define moment of inertia. Find the moment of inertia of a solid cylinder about an axis which is normal to the axis of the cylinder and passes through the centre of mass.
OR
State and prove the parallel axis theorem and perpendicular axis theorem.

A wheel with moment of inertia I 10 kg-m^2 is spinning at 2 rev/s on its axis. How large is the frictional torque, if the wheel makes 40 revolutions before it comes to a stop?

A sphere of mass 0·5 kg and diameter 1 m rolls without slipping with a constant velocity of 5 m/s. Calculate its total energy. Take moment of inertia of sphere about one of its diameters as 2/5 MR^2 .
OR
State and prove Work-Energy Theorem.

State and explain Newton's law of motion. When two bodies interact only through mutual forces, show that the net
momentum of the bodies does not change with time.
OR
Discuss one-dimensional elastic collisions between two bodies.

A particle is projected with an initial speed Vo at an angle 8 to the horizontal. Determine its angular momentum about the origin as a function of time.

In a nuclear fusion reaction, a deuteron of mass 2·01355u and a triton of mass 3.01550 u combine to give a neutron of mass 1·00867 u and an alpha particle of mass 4·00150 u. Calculate the energy released in the process.
One atomic mass 931.5 MeV/c^2.
OR
State Kepler's law of planetary motion.

State and prove Ampere's law. What is the· magnitude of force per 110 cm length of each of a pair of conductors of a direct current line carrying 10 Amperes and spaced 10 cm apart?
OR
State and explain Faraday's law.

Two square loops of sides 1 cm and 2 cm are kept in the same plane with their centres 40 cm apart. Calculate the mutual inductance.

What is displacement current? A parallel plate capacitor with circular plates of radius 10 cm separated by 5 mm is being charged by an external source. The charging current is 0·2 A Find the displacement current and rate of change of potential difference between the plates.
OR
Discuss energy density in electromagnetic waves. Also define Poynting vector.

Physical Constants:

e=1·6x10^-19 C
EO =8·854 x 10^-12 F/m
uo =4n x Wb/A-m
G =6·67 x 10^-11
Avogadro's number 6·022 x 10^26 atoms
me 9·1 x 10^-31 kg
mp 1.7 x 10^-27 Kg